Doc: Outdated links to eCAL Samples

[FlorianReimold]

The samples have been moved in the repo, but nobody updated the Documentation:

https://github.com/eclipse-ecal/ecal/blob/e9083719527fbaf05b181d806c3da1bd8f9e0ced/doc/rst/advanced/layers/tcp.rst?plain=1#L105

I guess there are more deep-links. A full-text search should reveal them.